Controlled pore glass is generally made from borosilicate glass. The general method for removing the soluble phase consists of bringing the phase separated borosilicate glass into contact with an aqueous solution. One such leaching treatment consists of placing the phase separated and annealed borosilicate glass into a hot water bath followed by subsequent acid leaching and water wash (see U.S. Pat. No. 3,843,341, the complete disclosure of which is hereby incorporated by reference). Other procedures describe a multistep leaching procedure consisting of: 1) contact with an acidic solution; 2) water wash; 3) contact with an alkaline solution; 4) water wash; 5) contact with a second acidic solution; and 6) a boiling water wash. (See U.S. Pat. No. 3,549,524, the complete disclosure of which is hereby incorporated by reference).
CPG is often used in applications such as adsorption, filtration and separation membranes. Additionally, CPG is often used in solid phase synthesis or solid phase extraction procedures. CPG offers a number of advantages over other solid phase materials, such as, chemical stability, high strength, and stability in organic solvents, high surface area, uniform pore size and uniform pore distribution.
CPG is amenable to a number of derivitization or functionalization procedures. These derivitization or functionalization procedures consist of chemically bonding organosilanes. (See U.S. Pat. No. 5,919,523, the complete disclosure of which is hereby incorporated by reference). The chemically reactive organosilanes then serve as an attachment point to covalently link a number of organic molecules. The surface modification provides linkages that are chemically stable and sufficiently long to decrease steric interference form the support. For example, CPG undergoing an epoxy silane or isothiocyante treatment will serve as an attachment point for NH2-modified oligos.
Currently there are a number of solutions for manufacturing controlled pore glass which require 1) heat treatment of borosilicate glass to phase separate and 2) leaching the phase separated borosilicate glass with aqueous solutions. Additionally, further treatment with alkaline aqueous solutions, such as, NaOH is often required. After each leaching step a significant quantity of wash is required to wash and flush the acidic leaching solution, alkaline leaching solutions and any remaining soluble materials. Some methods attempt to reduce the total number of treatments steps or precipitate leached borate (See U.S. Pat. No. 3,843,341, the complete disclosure of which is hereby incorporated by reference), but these solutions fail to meet the needs of the industry because large quantities of waste water is produced following leaching procedures.
It would be desirable to have a method of manufacturing CPG from phase separated borosilicate glass which can be used to reduce leach waste byproducts. It would also be desirable to have a method of manufacturing that would reduce the total volume of water required to manufacture CPG. It would also be desirable to have a method of manufacturing that would permit the discharge of waste products directly into publically owned treatment works. And finally it would be desirable to have a method of manufacturing that would reduce the quantity of wash water that must be treated before disposing into publically owned treatment works.